diff --git a/include/minja/minja.hpp b/include/minja/minja.hpp
index ec89bc7..9e92b72 100644
--- a/include/minja/minja.hpp
+++ b/include/minja/minja.hpp
@@ -2589,7 +2589,7 @@ inline std::shared_ptr<Context> Context::builtins() {
   globals.set("raise_exception", simple_function("raise_exception", { "message" }, [](const std::shared_ptr<Context> &, Value & args) -> Value {
     throw std::runtime_error(args.at("message").get<std::string>());
   }));
-  globals.set("tojson", simple_function("tojson", { "value", "indent" }, [](const std::shared_ptr<Context> &, Value & args) {
+  globals.set("tojson", simple_function("tojson", { "value", "indent", "ensure_ascii" }, [](const std::shared_ptr<Context> &, Value & args) {
     return Value(args.at("value").dump(args.get<int64_t>("indent", -1), /* to_json= */ true));
   }));
   globals.set("items", simple_function("items", { "object" }, [](const std::shared_ptr<Context> &, Value & args) {